Muffler



FIG. 1 is an isometric view of a front, top, and right side of an ornamental design for a muffler;

FIG. 2 is a top plan view of the muffler of FIG. 1;

FIG. 3 is a bottom plan view of the muffler of FIG. 1;

FIG. 4 is a rear elevational view of the muffler of FIG. 1;

FIG. 5 is a front elevational view of the muffler of FIG. 1;

FIG. 6 is a right side elevational view of the muffler of FIG. 1;

FIG. 7 is a left side elevational view of the muffler of FIG. 1; and,

FIG. 8 is an isometric view of the muffler of FIGS. 1-7 shown in a second state. 

CLAIM The ornamental design for a muffler, as shown and described. 